Description
Decapeptyl is a modified (D-Trp6) LH-RH. Like recently marketed buserelin and
leuprolide (I), it is useful in achieving medical castration in the treatment of advanced prostate cancer.
Originator
Tulane Univ. (USA)
Definition
ChEBI: An oligopeptide comprising pyroglutamyl, histidyl, tryptophyl, seryl, tyrosyl, D-tryptophyl, leucyl, arginyl, prolyl and glycinamide residues joined in sequence. It is an agonist analogue of gonadotropin-releasing hormone.
Brand name
Trelstar (Watson).
Biochem/physiol Actions
Potent LH-RH agonist with enhanced biological activity due to its slower rate of degradation. Like [D-Lys6]-LH-RH, the D-Trp6 analog has been shown to be effective against cancers expressing the LH-RH receptor. However, unlike the D-Lys6 analog, it is generally used in the unconjugated form.
Clinical Use
Triptorelin pamoate is another superagonist of GnRH, which like nafarelin acetate contains only
a single amino acid substitution (D-Trp6 for Gly6) when compared to the natural hormone. In the treatment of advanced prostate cancer, it is important to reduce serum
testosterone levels to very low levels, which can be achieved surgically by orchiectomy. When
this surgical method is unacceptable to the patient, an alternative approach is “chemical
castration,” which can be achieved by use of estrogen therapy, leuprolide,goserelin or histrelin acetates, and now, triptorelin pamoate. This product is available for IM
depot injection (monthly or every 3 months), wherein serum testosterone concentration drops to
a level generally seen in surgically castrated men.
Side effects
The side effects of Triptorelin: Painful or difficult urination, burning when you urinate, blood in the urine; bone pain; (in children) new or worsening signs of puberty; a seizure; chest pain or pressure, pain spreading to your jaw or shoulder; sudden numbness or weakness, slurred speech; increased pressure inside the skull - severe headaches, ringing in your ears, dizziness, nausea, vision problems, pain behind your eyes; loss of movement in any part of your body; high blood sugar - increased thirst, increased urination, hunger, dry mouth, fruity breath odor; or nerve problems - back pain, muscle weakness, problems with balance or coordination, severe numbness or tingling in your legs or feet, loss of bladder or bowel control.
Drug interactions
Potentially hazardous interactions with other drugs
None known
Metabolism
The metabolism of triptorelin in humans is unknown, but
it is thought to be hydrolysed in the plasma and excreted
in the urine as inactive metabolites.
Mode of action
Triptorelin is a gonadotrophin releasing hormone (GnRH) blocker. This means it stops messages from a part of the brain called the hypothalamus that tells the pituitary gland Open a glossary item to produce luteinising hormone. Luteinising hormone tells the testicles to produce testosterone Open a glossary item. So, blocking GnRH stops the testicles producing testosterone. Prostate cancer depends on testosterone to grow. So triptorelin can shrink the cancer or slow its growth. In women, it stops the ovaries Open a glossary item from producing oestrogen. Some breast cancers depend on oestrogen to grow. Lowering the level of oestrogen can slow or stop the growth of the cancer.
